Exception raised by tbwiki software

Traceback (most recent call last):
  File "/usr/lib/cgi-bin/server.cgi", line 55, in 
    main(req)
  File "/home/ubuntu/work/tbwiki/cgi-bin/tbwiki_engine.py", line 2490, in main
    print html
UnicodeEncodeError: 'ascii' codec can't encode character u'\xdf' in position 203: ordinal not in range(128)